1. Technical Field
The disclosure relates in general to an energy detection method and the energy detection circuit.
2. Description of the Related Art
Along with the wide popularity and rapid development of wireless communication, time division multiplex system has been widely used in communication system such as the Time Division Duplex Long Term Evolution (TD-LTE) protocol, the Worldwide Interoperability for Microwave Access (WiMAX) protocol and the Institute of Electrical and Electronics Engineers (IEEE) 802.16m protocol.
In the communication system based on frame structure, when the receiver starts to receive a signal, the strength and properties of the signal are unknown. Thus, in the current communication system, the distortion of signal amplitude tends to occur to the receiver, and error and shift may occur to the mechanism which uses the properties of the signal for synchronization. Conventionally, the initial position of the signal (that is, the initial time point of the frame structure) is obtained by the energy detection method, so that the receiver can activate its automatic gain control (AGC) mechanism to adjust the strength of the signal, so that the properties of the signal will not be jeopardized and synchronization can be achieved with higher accuracy.
In the current technologies, the energy detection method has a fixed energy threshold, and the initial position of the signal is determined when the energy of the input signal is greater than the threshold.